Question: Ever since Renata moved to her new home, she's been keeping track of the height of the tree outside her window. The variable $h$ models the height of the tree (in centimeters), $t$ years since Renata moved in. $h=210+33t$ How tall was the tree when Renata moved in?
Solution: When Renata first moved in, the number of years since she moved in, $t$, was $0$. We can calculate the height of the tree at that time: $\begin{aligned} h&=210+33t\\\\ h&=210+33(0)\\\\ h&=210+0 \\\\ h &= 210 \end{aligned}$ The tree's height when Renata moved in was $210$ centimeters.